The present invention relates to a standardized medical cognitive assessment tool. More specifically, the present invention relates to systems and methods for testing and evaluating cognitive ability that are particularly sensitive to mild cognitive impairment and are suitable for a variety of challenging groups, including the elderly, children, people with learning disorders or short attention spans, the mildly visually impaired, and others. The systems and methods described are a tool for a clinician to be able to track cognitive ability and diagnose mental conditions such as Alzheimer's or other forms of dementia, attention deficit disorder, or learning disorders.
Cognition is a general term for mental processes by which an individual acquires knowledge, solves problems, and plans activities. Cognitive skills include attention, visual/spatial perception, judging and decision-making, problem solving, memory and verbal function, among others. The functional levels of each of these skills can be studied alone or in combination for a particular individual.
Evaluation and quantification of cognitive ability has been a challenge to both scientists and clinicians. This information is important for enabling quick and accurate diagnoses, for directing treatments, and for tracking the patient's response to medical, surgical, or rehabilitation therapies. Particularly in the clinical arena, testing systems have been subject to problems of bias, both from the external environment and from individuals administering the tests. External biases may include language or culture gaps between the test content and the subject taking the test, or lack of familiarity with the mechanical aspects of the test, or any other external factor that may influence test taking ability. Potential biases from a test administrator include conversation between the administrator and the subject, or subjective observations by the administrator which may play a role in score determination. Furthermore, tests are typically administered without adequate consideration of the skill level of the subject being tested. The result of this type of oversight may be a test which is too easy or too difficult for a particular individual, causing “ceiling” or “floor” effects which essentially eliminate meaningful results. This effect is particularly apparent for mildly impaired individuals, for whom the testing scheme is too complex, either in terms of stimulus and response interfaces, or in terms of the level of questions. In addition, traditional tests cannot accurately judge reaction time, which is a factor that should be considered in evaluation of many cognitive skills. Generally, it would be desirable to be able to evaluate several aspects simultaneously and retain the option of scoring based on each of the skills being tested alone or in combination.
Most tests that are designed to measure cognitive skill level, such as IQ tests, merely measure function and provide a score. However, current testing systems do not evaluate the borderline region of functional ability which can indicate a normal versus a pathological state. For example, those with “mild cognitive impairment” whose level of cognitive function is transitional between normal and dementia are often not diagnosed in a systematic and reliable way. Furthermore, different levels of probability of various cognitive states are not provided. It would be desirable to have an objective testing system with specific multi-level criteria for determining whether intervention would be necessary or helpful.
Prior art testing systems have been developed to provide an interactive computerized way of measuring cognitive skills. U.S. Pat. No. 6,435,878 to Reynolds et al. discloses an interactive computer program for measuring and analyzing mental ability. Reynolds et al. disclose a system which presents a variety of auditory or visual stimuli, and interactively provides feedback and adjusts the level of the test based on received responses. The system tests for reaction time, memory, attention and decision-making processes. However, it is not a clinical tool which would be useful for a clinician in providing diagnostic information related to skill level or pathological state. Prior art systems such as the one disclosed in Reynolds et al. do not sufficiently expand the range of sensitivity to avoid ceiling or floor effects in mildly impaired individuals.
A neurological testing apparatus is described in U.S. Pat. No. 6,517,480 to Krass. This apparatus includes a microprocessing unit for carrying out test procedures, an interface to a sensory signal generating device, an interface to a reaction detecting device, and an interface to a memory for reading test procedures stored in the memory. The apparatus tests for abstract reasoning ability, visual memory, visual/motor perception, response time and grip strength. However, the apparatus lacks at least the following features: automated adaptability, utility for mildly visually impaired individuals, and a coherent reporting and analysis system.
Furthermore, the prior art systems do not provide tools for assessing individuals based on probabilities and sub-ranges of normal and abnormal diagnoses.
There is thus a widely recognized need for, and it would be highly advantageous to have, a testing system and method devoid of the above limitations.